Rocky Mountain Thunder

When the Democratic National Convention Committee announced Monday that Barack Obama would be delivering his acceptance speech from the roofless confines of Invesco Field at Mile High, local and national news outlets, each with their own reasons, were quick to jump on Mother Nature. Local dailies, knowing too well the potential for a perfect storm of summer-late-afternoon-rain, downtown rush hour and Invesco traffic, cautioned readers to expect a mess.

National reports referenced what they saw as worst-case scenarios: “Democratic Party officials [are]… praying that the thunderclouds that often roll across the Rockies in the summer won't rain on his spiel,” opined the L.A. Times, while the New York Times quoted Obama advisor Anita Dunn saying that the campaign had studied the historical weather patterns and would have contingency plans for foul weather.

As Westwordand other media guests learned as part of this week’s delayed convention walkthrough, “contingency plans” are synonymous with “rain or shine,” with the only real option—so far—to temporarily delay Obama’s speech until fairer conditions prevail.

But what is the real likelihood of the wet stuff? Of Rocky Mountain Thunder rolling forth, not from feet on stands but from threatening skies?

Bob Henson, meteorologist for the University Corporation for Atmospheric Research, headquartered in Boulder, analyzed the published National Oceanic and Atmospheric Administration (NOAA) day-by-day measurements for August rainfall in Denver since 1995. Of those thirteen years, only four have received noticeable rain -- more than a fifth of an inch -- in the three days surrounding the 28th of August. Thunderstorms, with negligible or trace rain, have occurred far more frequently, in eleven of the last thirteen years. On average, with data spanning back to 1971, Henson notes that recent years have been drier than the overall historical record, which predicts a one-in-four chance of getting measurable rain on any given day in August.

Not bad odds, particularly for the political types whose professional lives are staked daily on the fifty-fifty chance of scraping together a bare majority on the issue-du-jour. Call this an added and thoroughly unexpected benefit of holding the convention in Denver—George Bush floated the idea of moving his acceptance speech in 2004 from Madison Square Garden to Yankee Stadium—as NYC, this year’s other Democratic host finalist, averages nearly three times the amount of rain for the same span of days in August.

Even allowing for some patches of rain or thunder, the chances for a fine closing evening for the convention are pretty good. In the two worst late August rainstorms of recent record, in 1999 and 2000, the total precipitation for any one day was less than an inch. Factor in the duration of an average Front Range downpour is all of an eye-blink and that the majority makeup of the crowd—party delegates and Obamanaiacs—will be jazzed no matter what the weather, and John McCain better wield a pretty hefty rainstick with top-notch voodoo to open the heavens wide enough to drown this parade. -- Joe Horton

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